package Util;

import com.mysql.cj.jdbc.MysqlDataSource;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtil {
    //构造方法私有化，防止newDBUtil，单例模式中的重要特征
    private DBUtil(){
    }
    //数据源
    private static DataSource dataSource=null;
    //数据库连接串
    private static final String URL="jdbc:mysql://127.0.0.1:3306/test_db03?characterEncoding=utf8" +
            "&allowPublicKeyRetrieval=true&useSSL=false";
    //用户名
    private static final String USER="root";
    //密码
    private static final String PASSWORD="123456 ";
    //当类加载到JVM时，执行数据的初始化
    static {
        MysqlDataSource mysqlDataSource=new MysqlDataSource();
        mysqlDataSource.setURL(URL);
        mysqlDataSource.setUser(USER);
        mysqlDataSource.setPassword(PASSWORD);
        dataSource=mysqlDataSource;
    }

    public static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }

    public static void close(ResultSet resultSet, PreparedStatement statement,Connection connection){
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if(statement!=null){
            try {
                statement.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
}
